The proposed work involves detailed studies of the mycoplasmas at both cellular and subcellular levels. The previously reported effect of cytochalasin B on mycoplasmas will be investigated to see whether the mycoplasma polymerizing protein fraction contains a cytochalasin B binding protein, the effect of cytochalasin B on the polymerization reaction, and analysis of the polymerization product. Studies will also be carried out to survey mycoplasma species for their capabilities in the repair of ultraviolet light induced damage. Data on 16S ribosomal RNA oligonucleotide sequences will be analyzed to allow construction of mycoplasma phylogeny.